(a) Make a labelled diagram to show the internal structure of the mammalian ear. (b) Describe the mechanism of hearing in mammals. (c) State two ways of car...

(a) Labelled diagram of the internal structure of the mammalian ear

(b) Mechanism of hearing in mammals

1. The pinna collects sound waves and directs them through the auditory canal (auditory meatus) to the tympanic membrane or ear drum.
2. The sound waves make the ear drum vibrate.
3. These vibrations are transmitted through, and amplified by, the three ossicles: malleus, incus and stapes.
4. The stapes transmits the vibrations to the oval window. This causes the fluid in the cochlea to vibrate.
5. The vibrations stimulate the sensory hair cells in the organ of Corti in the cochlea, producing nerve impulses.
6. The auditory nerve carries the impulses to the brain, where they are interpreted as sound.

(c) Care of the ear

1. Keep the outer ear clean, but do not insert pins, sticks or other sharp objects into the ear canal.
2. Avoid excessive loud noise and consult a doctor promptly if there is ear pain, discharge or infection.